Preservation evaluation method of Chinese traditional shadow puppet relics based on pixel lattice and membership function

Lei, Xinyi; Li, Long; Liu, Xinyu; Du, Zhiyan

doi:10.1186/s40494-023-01006-2

Heritage Science

Table 1 Deconstruction results of pixel lattice for digital photo of shadow puppet artifact's flesh surface (Serial Number: 6Y1A7598)

From: Preservation evaluation method of Chinese traditional shadow puppet relics based on pixel lattice and membership function

Relative to \({O}_{k}\) point	Calculation item	White	Yellow	Red	Blue	Black
Monochrome region \(\it k\)	\({N}_{k}\)	66854	68023	11810	12025	19027
Monochrome region \(\it k\)	\(P_{{\text{k}}}\) (%)	37.61	38.27	6.64	6.77	10.71
Color tolerance \(\it i\) = 50	\({N}_{k50}\)	8844	15645	4696	9807	16851
	P_k (%)	13.23	23.00	39.76	81.56	88.56
	ΔP_K(50−0) (%)	13.23	23.00	39.76	81.56	88.56
Color tolerance \(\it i\) = 80	\({N}_{k80}\)	13093	32572	10261	11276	17815
	\({P}_{k80}\)(%)	19.58	47.88	86.88	93.77	93.63
	ΔP_K(80−50) (%)	6.36	24.88	47.12	12.21	5.06
Color tolerance \(\it i\)= 100	\({N}_{k100}\)	14436	63991	10827	11552	18071
	\({P}_{k100}\)(%)	21.59	94.07	91.68	96.07	94.98
	\(\Delta P_{k(100 - 80)} \,(\% )\)	2.01	46.19	4.79	2.30	1.35
Color tolerance \(\it i\) = 120	\({N}_{k120}\)	17880	68000	11070	11693	18276
	\({P}_{k120}\)(%)	26.74	99.97	93.73	97.24	96.05
	ΔP_K(120−100) (%)	5.15	5.89	2.06	1.17	1.08
Color tolerance \(\it i\) = 150	\({N}_{k150}\)	58200	68017	11240	11794	18445
	\({P}_{k150}\)(%)	87.06	99.99	95.17	98.08	96.94
	\(\Delta P_{k(150 - 120)} \,(\% )\)	60.31	0.02	1.44	0.84	0.88
Total pixels	\({N}_{0}\)	177739

Monochrome region \(\it k\): It represents a region of a single color, such as white, yellow, red, blue, or black
\({O}_{k}\): The monochromatic standard point \({O}_{k}\) is determined based on the average and actual offset of the overall distribution of the pixel points chromaticity in the RGB color space for the single color region \(\it k\)
\(\mathrm{i}/\mathrm{j}\): \(\mathrm{i}\) and \(\mathrm{j}\) represent the color difference value in the RGB color space between the monochromatic standard point \({O}_{k}\) of the artifact and the pixel points in region k
Color tolerance 50: It represents the color difference value i = 50 between the monochromatic standard point \({O}_{k}\) of the artifact and the pixel points in region k in the RGB color space
\({N}_{k}\): The number of pixel points in each region \(\it k\)
\({P}_{k}\): The area proportion of the monochromatic region \(\it k\) in the whole five basic color area
\({P}_{ki}\): The proportion of the selected pixel area with a color tolerance condition of \(\it i\) in region \(\it k\)
\({N}_{ki}\): The number of pixel points that can be selected within region \(\it k\) when the color tolerance is set to relative \(\it i\) to the monochromatic standard point \({O}_{k}\)
\(\Delta {P}_{k(i-j)}\): It is named the monochrome pixel color rendering ratio, and it represents the proportion of the area within the monochromatic region \(\mathrm{k}\) relative to the entire RGB color space at the monochromatic standard point, subject to a color tolerance condition between \(\it j\) and \(\it i\)
\({N}_{k50}\): The number of pixels that can be selected within region \(\it k\) with a color tolerance of \(\it i\)=50 relative to the monochromatic standard point \({O}_{k}\)
\({P}_{k50}\): The proportion of the selected pixel area under the color tolerance condition \(\it i\)=50 in region \(\it k\)
\(\Delta P_{k(50 - 0)}\) : The monochrome pixel color rendering ratio represents the proportion of the area within the monochromatic region \(\it k\) relative to the entire RGB color space at the monochromatic standard point, under a color tolerance condition of [\(\it j\), \(\it i\)] where \(\it i\)=50 and \(\it j\)=0
\({N}_{0}\): Denotes the total number of pixel points in the "five basic color" monochrome region \(\it k\) of the shadow puppet

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